[sangnoir]

> If not touch screen activity for a long time, or when simply the screen is locked, then why is the camera on?

Because the OS shouldn't be making assumptions about applications' interaction models. People tend to write apps that OS creators never dreamed about. There are legitimate reasons for resource usage (camera) to continue without user interaction.From the top of my head, I can imagine writing a baby-monitor app that uses camera to stream video to my phone in the other room using wifi.

The resource-limiting heuristics have to be impossibly good, otherwise it gets in the way of useful apps.

[jordanthoms]

One way of handling this is to have a separate permission - Use camera, which allows an app to use it for a limited time with the user interacting and while in foreground, and a 'Background Camera' permission which your baby-monitor app would request. Perhaps make the permissions dialog for the background permission scarier so developers have an incentive to use the less privileged permission.

This would work nicely for GPS etc - sure, I want to be able to have My Tracks keep GPS on for 3 hours, but I don't need Uber to be able to do that - and their app has a nasty habit of forgetting to turn the GPS off if you leave it at the wrong time.